no clear evidence of a relationship (see Table 3). The correlation be- 

 tween number of peaks and Hg is less than 0.3 at all locations (Table 

 4). The joint distribution table of number of major spectral peaks ver- 

 sus period corresponding to the highest spectral peak at each location 

 also shows little evidence of a relationship (Table 5). The correlation 

 between number of peaks and Tp is also very low (Table 4). For most 

 .wave conditions the occurrence of secondary spectral peaks does not 

 appear to be systematically related to Hg and Tp. The overall sta- 

 tistics on multiple peaks as indicators of multiple wave trains should 

 be reasonably correct. 



Several other attempts have been made to quantify the likelihood 

 of having multiple wave trains. Shepard and Inman (1951) report visual 

 wave observations to identify secondary and dominant wave trains from 

 the Scripps pier in southern California during a 10-month period. They 

 report secondary wave trains in 56 percent of 302 observations. This 

 figure may be an underestimate because of the difficulty of visually 

 identifying secondary trains, but is reasonably consistent with the 

 Huntington Beach gage data. 



Table 3; Percentage c 



f cases 1 



n each s 



ignificant height group 



corresponding to number of major spectral peaks. 



ll„(cm) 



Major spectral pouks 



Cases 





1 1 2 1 3 1 4 1 5 





Nags Head, N.C. | 



to 30 



29 



39 



29 



3 



.1 



38 



30 to 61 



40 



45 



14 



2 



- 



301 



61 to 91 



36 



42 



19 



2 



- 



208 



91 to 122 



20 



58 



21 



1 



1 



158 



122 to 152 



22 



59 



17 



2 



- 



95 



152 to 183 



25 



44 



22 



7 



2 



59 



183 to 213 



13 



50 



31 



6 



- 



52 



213 to 244 



21 



50 



25 



4 



- 



28 



244 to 274 



-.-1 



60 



40 



__1 



- 



5 



274 to 305 



100 



__1 



_.l 



— 





1 



Naples, Fla. | 



to 30 



45 



45 



9 



1 



- 



482 



30 to 61 



36 



42 



19 



2 



- 



288 



61 to 91 



34 



45 



16 



1 



3 



73 



91 to 122 



15 



55 



30 



-- 



- 



20 



122 to 152 



33 



67 



"" 



— 



- 



3 



Michigan City, Ind. (pressure gage] | 



to 30 



17 



50 



29 



4 



- 



24 



30 to 61 



18 



64 



18 



-- 



- 



11 



61 to 91 



22 



37 



26 



15 



- 



27 



91 to 122 



30 



50 



20 



-- 





20 



122 to 152 



33 



33 



33 



-- 





12 



152 to 183 



64 



18 



9 



9 





11 



183 to 213 



55 



36 



9 



-- 



- 



11 



213 to 244 



25 



63 



13 



-- 



- 



8 



244 to 274 



50 



50 



-- 



— 



- 



2 



2 74 to 305 



100 



— 



— 



— 



- 



1 



Huntington Beach, Calif. | 



to 30 















30 to 61 



32 



45 



23 



-- 



- 



31 



61 to 91 



37 



50 



11 



2 



- 



311 



91 to 122 



36 



49 



13 



2 



- 



264 



122 to 152 



36 



46 



16 



3 



- 



90 



152 to 183 



44 



41 



12 



3 



- 



34 



183 to 213 



36 



45 



18 



-- 



- 



11 



213 to 244 



67 



33 



-- 



— 





3 



244 to 274 







100 



-- 



— 



- 



1 



274 to 305 



— 



100 



-- 



-- 



- 



1 



'No observed cases for combinations of H- and number of peaks. 



42 



